1/9 june 2001 n high speed: t pd = 5.4 ns (typ.) at v cc = 5v n low power dissipation: i cc = 4 m a (max.) at t a =25c n compatible with ttl outputs: v ih = 2v (min.), v il = 0.8v (max) n power down protection on inputs & outputs n symmetrical output impedance: |i oh | = i ol = 8 ma (min) n balanced propagation delays: t plh @ t phl n operating voltage range: v cc (opr) = 4.5v to 5.5v n pin and function compatible with 74 series 244 n improved latch-up immunity n low noise: v olp = 0.9v (max.) description the 74vhct244a is an advanced high-speed cmos octal bus buffer (3-state) fabricated with sub-micron silicon gate and double-layer metal wiring c 2 mos technology. g enable input governs four bus buffers. this device is designed to be used with 3 state memory address drivers, etc. power down protection is provided on all inputs and outputs and 0 to 7v can be accepted on inputs with no regard to the supply voltage. this device can be used to interface 5v to 3v since all inputs are equipped with ttl threshold. all inputs and outputs are equipped with protection circuits against static discharge, giving them 2kv esd immunity and transient excess voltage. 74vhct244a octal bus buffer with 3 state outputs (non inverted) pin connection and iec logic symbols order codes package tube t & r sop 74vhct244am 74vhct244amtr tssop 74VHCT244ATTR tssop sop
74vhct244a 2/9 input equivalent circuit pin description truth table x : dont care z : high impedance absolute maximum ratings absolute maximum ratings are those values beyond which damage to the device may occur. functional operation under these conditi ons is not implied 1) output in off state 2) high or low state pin no symbol name and function 11g output enable input 2, 4, 6, 8 1a1 to 1a4 data inputs 9, 7, 5, 3 2y1 to 2y4 data outputs 11, 13, 15, 17 2a1 to 2a4 data inputs 18, 16, 14, 12 1y1 to 1y4 data outputs 19 2g output enable input 10 gnd ground (0v) 20 v cc positive supply voltage inputs output g an yn lll lhh hxz symbol parameter value unit v cc supply voltage -0.5 to +7.0 v v i dc input voltage -0.5 to +7.0 v v o dc output voltage (see note 1) -0.5 to +7.0 v v o dc output voltage (see note 2) -0.5 to v cc + 0.5 v i ik dc input diode current - 20 ma i ok dc output diode current 20 ma i o dc output current 25 ma i cc or i gnd dc v cc or ground current 50 ma t stg storage temperature -65 to +150 c t l lead temperature (10 sec) 300 c
74vhct244a 3/9 recommended operating conditions 1)output in off state 2) high or low state 3) vin from 0.8v to 2v dc specifications ac electrical characteristics (input t r = t f = 3ns) (*) voltage range is 5.0v 0.5v symbol parameter value unit v cc supply voltage 4.5 to 5.5 v v i input voltage 0 to 5.5 v v o output voltage (see note 1) 0 to 5.5 v v o output voltage (see note 2) 0 to v cc v t op operating temperature -55 to 125 c dt/dv input rise and fall time (see note 3) (v cc = 5.0 0.5v) 0 to 20 ns/v symbol parameter test condition value unit v cc (v) t a = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. v ih high level input voltage 4.5 to 5.5 222v v il low level input voltage 4.5 to 5.5 0.8 0.8 0.8 v v oh high level output voltage 4.5 i o =-50 m a 4.4 4.5 4.4 4.4 v 4.5 i o =-8 ma 3.94 3.8 3.7 v ol low level output voltage 4.5 i o =50 m a 0.0 0.1 0.1 0.1 v 4.5 i o =8 ma 0.36 0.44 0.55 ioz high impedance output leakage current 4.5 to 5.5 v i = v ih or v il v o = 0v to 5.5v 0.25 2.5 2.5 m a i i input leakage current 0 to 5.5 v i = 5.5v or gnd 0.1 1.0 1.0 m a i cc quiescent supply current 5.5 v i = v cc or gnd 22020 m a i cc additional worst case supply current 5.5 one input at 3.4v, other input at v cc or gnd 1.35 1.5 1.5 ma i opd output leakage current 0 v out = 5.5v 0.5 5.0 5.0 m a symbol parameter test condition value unit v cc (*) (v) c l (pf) t a = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. t plh t phl propagation delay time 5.0 15 5.4 7.4 1.0 8.5 1.0 8.5 ns 5.0 50 5.9 8.4 1.0 9.5 1.0 9.5 t plz t phz output disable time 5.0 15 rl = 1k w 7.7 10.4 1.0 12.0 1.0 12.0 ns 5.0 50 8.2 11.4 1.0 13.0 1.0 13.0 t pzl t pzh output enable time 5.0 50 rl = 1k w 8.8 11.4 1.0 13.0 1.0 13.0 ns
74vhct244a 4/9 capacitive characteristics 1) c pd is defined as the value of the ics internal equivalent capacitance which is calculated from the operating current consumption without load. (refer to test circuit). average operating current can be obtained by the following equation. i cc(opr) = c pd x v cc x f in + i cc /8 (per gate) dynamic switching characteristics 1) worst case package. 2) max number of outputs defined as (n). data inputs are driven 0v to 3.0v, (n-1) outputs switching and one output at gnd. 3) max number of data inputs (n) switching. (n-1) switching 0v to 3.0v. inputs under test switching: 3.0v to threshold (v ild ), 0v to threshold (v ihd ), f=1mhz. symbol parameter test condition value unit t a = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. c in input capacitance 6101010pf c out output capacitance 10 pf c pd power dissipation capacitance (note 1) 18 pf symbol parameter test condition value unit v cc (v) t a = 25c -40 to 85c -55 to 125c min. typ. max. min. max. min. max. v olp dynamic low voltage quiet output (note 1, 2) 5.0 c l = 50 pf 0.9 1.1 v v olv -1.1 -0.9 v ihd dynamic high voltage input (note 1, 3) 5.0 2.0 v ild dynamic low voltage input (note 1, 3) 5.0 0.8
74vhct244a 5/9 test circuit c l =15/ 50pf or equivalent (includes jig and probe capacitance) r l = r 1 = 1k w or equivalent r t = z out of pulse generator (typically 50 w ) waveform 1: propagation delays (f=1mhz; 50% duty cycle) test switch t plh , t phl open t pzl , t plz v cc t pzh , t phz gnd
74vhct244a 6/9 waveform 2: output enable and disable time (f=1mhz; 50% duty cycle)
74vhct244a 7/9 dim. mm. inch min. typ max. min. typ. max. a 2.65 0.104 a1 0.1 0.2 0.004 0.008 a2 2.45 0.096 b 0.35 0.49 0.014 0.019 b1 0.23 0.32 0.009 0.012 c 0.5 0.020 c1 45 (typ.) d 12.60 13.00 0.496 0.512 e 10.00 10.65 0.393 0.419 e 1.27 0.050 e3 11.43 0.450 f 7.40 7.60 0.291 0.300 l 0.50 1.27 0.020 0.050 m 0.75 0.029 s8 (max.) so-20 mechanical data po13l
74vhct244a 8/9 dim. mm. inch min. typ max. min. typ. max. a 1.2 0.047 a1 0.05 0.15 0.002 0.004 0.006 a2 0.8 1 1.05 0.031 0.039 0.041 b 0.19 0.30 0.007 0.012 c 0.09 0.20 0.004 0.0089 d 6.4 6.5 6.6 0.252 0.256 0.260 e 6.2 6.4 6.6 0.244 0.252 0.260 e1 4.3 4.4 4.48 0.169 0.173 0.176 e 0.65 bsc 0.0256 bsc k0 80 8 l 0.45 0.60 0.75 0.018 0.024 0.030 tssop20 mechanical data c e b a2 a e1 d 1 pin 1 identification a1 l k e 0087225c
74vhct244a information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result f rom its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specificati ons mentioned in this publication are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of stmicroelectronics. ? the st logo is a registered trademark of stmicroelectronics ? 2001 stmicroelectronics - printed in italy - all rights reserved stmicroelectronics group of companies australia - brazil - china - finland - france - germany - hong kong - india - italy - japan - malaysia - malta - morocco singapore - spain - sweden - switzerland - united kingdom ? http://www.st.com 9/9
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